Semiconductors exhibit large optical nonlinearities near the band edge because of resonance enhancement. Optical bistability occurs when the optical nonlinearities are coupled with feedback. In bulk GaAs and GaAs-AlGaAs multiple-quantum-well superlattices, the nonlinearity arising from the presence of the free-exciton resonance has produced room-temperature optical bistability with a few milliwatts of power. The formation of biexcitons in CuCl, the saturation of the bound exciton on CdS, and band-filling effects in InSb, InAs, and HgCdTe lead to observation of bistability in these materials. A bistable étalon can be operated in an optical-gate mode to generate optical analogs of electronic gates such as AND, OR, and NOR. It has been demonstrated that a GaAs optical NOR gate responds in ˜1 pseC, using only;S3 pJ of energy. However, because of the carrier lifetime of a few nanoseconds, the repetition rate of the NOR gate is now limited to a few hundred megahertz.
|Original language||English (US)|
|Number of pages||13|
|Journal||Journal of the Optical Society of America B: Optical Physics|
|State||Published - Jul 1985|
ASJC Scopus subject areas
- Statistical and Nonlinear Physics
- Atomic and Molecular Physics, and Optics